Unbranded transistors - important information about datasheet reading

Thread Starter

PaulEngineer

Joined Dec 21, 2016
217
Hi everyone. I send this message for everyone new to electronics as a warning to be careful and aware of how do you read a transistor datasheet. Never rely only on datasheets. Some transistor pinouts differ from manufacturer to manufacturer although they have the same model. Ignoring that, you can easily damage your transistor, without knowing the reason. Some semiconductor manufacturers are indicating their specific transistor model in their datasheets, and indicating their pinout numbers in different way, so not all of them are the same. For the example of the same model BF199, there are some different types of datasheets. Some of them may be old, some of them are new. Especially for the unbranded transistors. There you should be extra careful! Always use a multimeter that supports hFE reading. If you don't have that, use diode testing mode, but hFE is a must to easily get the correct pinout.
 

Thread Starter

PaulEngineer

Joined Dec 21, 2016
217
Hi everyone. I send this message for everyone new to electronics as a warning to be careful and aware of how do you read a transistor datasheet. Never rely only on datasheets. Some transistor pinouts differ from manufacturer to manufacturer although they have the same model. Ignoring that, you can easily damage your transistor, without knowing the reason. Some semiconductor manufacturers are indicating their specific transistor model in their datasheets, and indicating their pinout numbers in different way, so not all of them are the same. For the example of the same model BF199, there are some different types of datasheets. Some of them may be old, some of them are new. Especially for the unbranded transistors. There you should be extra careful! Always use a multimeter that supports hFE reading. If you don't have that, use diode testing mode, but hFE is a must to easily get the correct pinout.
Im apologize for the inconvenience. There were been an error deleting most of the content of that thread, so I'm apologize for the inconvenience caused by this error
 

dl324

Joined Mar 30, 2015
15,113
Never rely only on datasheets. Some transistor pinouts differ from manufacturer to manufacturer
I'm skeptical of this. There is little point in using standard part numbers if the devices aren't essentially drop-in replacements.

Please cite some examples.
 

Thread Starter

PaulEngineer

Joined Dec 21, 2016
217
I'm skeptical of this. There is little point in using standard part numbers if the devices aren't essentially drop-in replacements.

Please cite some examples.
2 datasheets different from each other

https://pdf1.alldatasheet.com/datasheet-pdf/view/16194/PHILIPS/BF199.html

https://pdf1.alldatasheet.com/datasheet-pdf/view/75216/MICRO-ELECTRONICS/BF199.html

Unbranded BF199 with the model BF199 PH 11. The default pinout i know for BF199 is CEB from the front view with pins looking down. The ones i bought was BEC from the same exact view. That's why I told, be careful. Some transistor are not the same. There was a detailed message before that one, but due to some error, most of its content just deleted without me knowing why. The important point is to always have a multimeter on the hand just to make sure that the transistor is good and as described in the datasheets. I burnt many transistors just because of that mistake.
 
Last edited:

MrSalts

Joined Apr 2, 2020
2,354
You mean, they couldn't be the same exact BF199? In such case, i mentioned that in that deleted content
There are usually some additional numbers, letters and hyphens if a specific transistor is in a non-standard package. Check the complete part number on the device (or check on the outer packaging). Compare that number to the detailed number on the datasheet - usually a page near the end discussing the painful details of the package size, outer package size and pin assignments.

Just because the details are in the fine print that is boring to read doesn't mean you can claim it is wrong or different or omitted. It's just painful to read.

Another possibility - a customer requested a special run of the transistor that were never supposed to get out in the wild and you bought them from a scrap-dealer. Any reputable distributor would handle parts with accurate datasheets. If you bought from a reputable distributor, read the details of the datasheet.
 

Thread Starter

PaulEngineer

Joined Dec 21, 2016
217
There are usually some additional numbers, letters and hyphens if a specific transistor is in a non-standard package. Check the complete part number on the device (or check on the outer packaging). Compare that number to the detailed number on the datasheet - usually a page near the end discussing the painful details of the package size, outer package size and pin assignments.

Just because the details are in the fine print that is boring to read doesn't mean you can claim it is wrong or different or omitted. It's just painful to read.

Another possibility - a customer requested a special run of the transistor that were never supposed to get out in the wild and you bought them from a scrap-dealer. Any reputable distributor would handle parts with accurate datasheets. If you bought from a reputable distributor, read the details of the datasheet.
There is nothing more written on a package except those solid BF199 PH 11. No part numbers, nothing. Just that. I bought them from aliexpress. Decided to give a chance. 10 transistor packages for 1,10 dollars.. If i remember well. I gave a chance because in Greece, nobody sells this transistor, and I don't know why. I was repairing 2 radios as an electronic hobbyist, that one of them held transistors BF199 and the other held BF494. Anyway, i have the habit to always check the datasheet before using the transistor, spot it's characteristics, and the most important thing, to check its pinout. So i replaced 2 broken transistors with the new ones. I powered the radio, i saw it doesn't work. I replaced them with new ones, same thing. I was sure i installed them correctly. So what to do, i bought BF199 with the brand from Fairchild i think. There was an F in the packaging. I installed both of them, and it suddenly worked. I took the transistors to check them up, by the datasheet pinouts, my multimeter shown OL in most cases. So i decided to measure the 1st pin with red probe and the next two with the black probe. Suddenly it shown both times the value of 0.778 which meant they were perfectly working. I placed the transistor in hFE, tried the pin combination to find out its correct pinouts. Their hFE was 80-84. But the pinouts were reversed. That's why i learnt from my mistakes, and realized that it is always necessary to never fully rely on datasheets and always double check the components before their installation.
 

Ya’akov

Joined Jan 27, 2019
6,561
DMMs with an hFE range are notoriously low quality meters.

But you can get an ATMega328-based LCR/Transistor Tester.

For a little more than $20 you can get a meter that will tell you the pinout, type (NPN, PNP, NMOS, PMOS), and parameters hFE, Vbe, and Ic. It can characterize diodes, including LEDs, and flashes them so you can see the color. It also provides the functionality of an LCR meter, though not with laboratory precision accurate enough for hobbyist and most practical work.
 

Thread Starter

PaulEngineer

Joined Dec 21, 2016
217
In this one example, there is a 3D model which has the ECB under the component. But exactly near that, if you look closely there is the bottom view which states CBE (the correct pinout). So what is the right one? ECB or CBE? As someone here said, this is horrible datasheet model pinout. Next time i will buy from known manufacturers like NXP, FAIRCHILD, NATIONAL SEMICONDUCTOR, STMICROELECTRONICS, TEXAS INSTRUMENTS etc, as they have serious and easy to read datasheets. And this will be a lesson for me, and for everyone new who wants to make electronics as a hobby.
1) Never buy unbranded transistors.
2) Always check the transistor condition even if you are completely sure you bought the right components
 

sagor

Joined Mar 10, 2019
754
Something wrong with the second datasheet. While the bottom view is correct, the datasheet title says BC183 (and BC213), but the pinout diagram shows BC184/BC214. A datasheet with a mistake like that should not be trusted. Someone pasted the wrong pinout diagram onto that datasheet.
 

Thread Starter

PaulEngineer

Joined Dec 21, 2016
217
I propose changing the warning to this:

When using electronic components always try to obtain the manufacturer’s data sheet for the part you intend to use. Specifications for parts with the same or similar part numbers often vary from from one manufacturer to another.
Totally agree
 

Thread Starter

PaulEngineer

Joined Dec 21, 2016
217
No, i meant they might not even be any version of bf199.

Edited to add: both datasheets you posted show the same pinout.
1) Do you think so? But on the package there is BF199 (i mean i have some spare pieces) and I think it's from Philips, as I seen another one BF199 PH 96 or 94. And it was from Phillips. But when I seen Phillips datasheet, it was completely different from my transistor. I don't know. I will never again buy from Aliexpress.

2) Maybe. Sometimes even I can be wrong as a new electronic hobbyist I am
 

DickCappels

Joined Aug 21, 2008
9,317
I hear you. Stick to authorized distributors to the extent possible. I have been buying from authorized electronics distributors for nearly 50 years. There will always be bad stuff out there, and sometimes you find flaky distributors. Even at my ripe old age I sometimes buy junk by accident, but I have cut way back on orders from gray market distributors because under the pressure (or opportunity) caused by the parts shortage, many fakes and sub-standard parts have shown up. Don't ever let your guard down.
 
Top